Articles » Traditional vs. Secure Beamforming in 6G Wireless

Traditional vs. Secure Beamforming in 6G Wireless

6g traditional beamforming secure beamforming wireless security physical layer security

Introduction : In the 5G era, we have seen beamforming as primary tool for efficiency. It was designed to overcome signal loss (i.e. path loss) at higher frequencies by focusing energy into tight beam much like flashlight.

In the 6G era, beamforming technique is evolving as tool for security. Physical layer security is going to be standard in 6G technology. In 6G, secure beamforming ensures signals are strong like traditional beamforming and also mathematically unreadable to anyone else outside the intended path.

Let us understand how these two approaches differ in objectives, mechanics and implementations.

Traditional Beamforming (Performance Centric)

  • The goal is to maximize SNR at legitimate receiver.
  • The idea here is to make the signal as loud and clear such that user can receive it.
  • This technique ignores eavesdropper and hence he/she can also receive this high quality signal. This makes the connection vulnerable.

Secure Beamforming (Secrecy Centric)

  • The goal is to maximize “secrecy rate”, which is difference between user’s capacity and eavesdropper’s capacity (Cs = Cuser - Ceavesdropper).
  • The idea here is make the signal clear for the user, but simultaneously act as jammer toward the eavesdropper.
  • Due to wide secrecy gap, eavesdropper can not decode the data.

How Secure Beamforming works

It utilizes spatial degrees of freedom available in massive mimo using multiple antennas. It does following two tasks.

  1. It directs the data signal toward the legitimate user similar to traditional.
  2. “Artificial noise injection” concept is used in which antennas transmit noise signal into all the directions except the user’s direction. Any eavesdropper located outside that specific angle is blasted with artificial noise, degrading their channel quality to zero.

Comparison

FeatureTraditional Beamforming applicationSecure Beamforming application
Reconfigurable Intelligent Surfaces (RIS)Used to reflect signals around obstacles to reach a user in a dead zone.Used to reflect the signal to the user while simultaneously reflecting “destructive interference” toward a known eavesdropper.
Massive MIMOUses excess antennas to serve more users (Spatial Multiplexing).Uses excess antennas to generate “Jamming Signals” that blind eavesdroppers without needing extra power.
Non-Terrestrial Networks (Satellites)Focuses beams to maximize coverage on the ground.Focuses beams to specific GPS coordinates while nulling signal reception in hostile geographic areas.

Summary :

Traditional Beamforming is about Optimization; getting the data from Point A (Transmitter) to Point B (legitimate Receiver) as efficiently as possible. Secure Beamforming is about differentiation; ensuring that Point B (legitimate receiver) can hear the data, while ensuring that Point C (i.e. eavesdropper or attacker) hears nothing but static. For 6G, secure beamforming transforms the network infrastructure itself into a defensive weapon.